Series lamp circuit



9 1941- H. .1. MccAFh-HY 2,28,512

SERIES LAMP CIRCUIT Filed Oct. 26, 1940 Patented Dec. 30, 1941 STTES PATENT OFFl SERIES LAMP CIRCUIT Application October 26, 1940, Serial No. 362,970

2 Claims.

This invention relates to electric gaseous discharge lamps and in particular to apparatus for operating such lamps.

Since discharge lamps require a ballasting device in series with them, an object of this invention is to obtain a simple yet efficient starting apparatus therefore.

Another object is to obtain a starting apparatus for two or more electric gaseous discharge lamps which will cause all the lamps to go on at exactly the same time.

A further object is to obtain a starting apparatus for fluorescent lamps that may readily be adapted to smaller sized lamps for domestic use.

Other objects, advantages and features will be apparent from the specifications which follow, taken in conjunction with the accompanying drawing in which:

Figure 1 is a schematic diagram of the series circuit employing an auto-transiormer, a condenser and a choke coil.

Figure 2 is a schematic diagram of the series lamp circuit connected directly to the line with an incandescent lamp as a ballast.

In Figure l, the power line l and 2 is connected in series with the auto-transformer 3. The lines 4 and from the transformer 3 are connected in series with one end of the filaments 9 and I0, respectively, of the lamps H and I2, the line 4 being connected through the choke coil l3, and the condenser 6 of about 2 microfarads being connected across lines 4 and 5 for power factor correction purposes. The secondary of the transformer 3 gives a voltage of 350 volts across lines 4 and 5. If this transformer 3, is of the leakage reactance type, the inductance coil l3 may, in some cases, be omitted.

Lines 14 and i5 from the other end of the filaments 9 and if] respectively of lamps II and i2 are connected to the filaments l6 and I! through the switch l8, the condenser l9 and the transformer 20. The filaments l6 and ll of lamps H and I2 respectively, are connected in series with the secondary of the transformer 20.

The inductance coil IS on line A in conjunction with the primary of the transformer cuts down the flow of current so that there will be about .700 ampere through the filaments while they are being heated during the starting operation. The switch l8 which is normally closed as is shown in Figure 1 is so timed as to open when the filaments have become sufficiently heated to permit the discharge across the lamp to start.

The condenser 15 may be about .01 microfarad.

The transformer 20 is such that the primary switch for each lamp. the possibility of having two switches timed slightly different and thus causing the lamps to go on at different times is eliminated. By connecting the lamps in this manner there is a saving of one switch and one choke for each set of two lamps. Although I have illustrated my circuit with two lamps, more than two may very readily be hooked up in the same circuit by adding another transformer so that the filament 9 of lamp l I would be connected in series to a filament of the third lamp through the new transformer. By providing the proper ratio in the transformers, any number of lamps may be added.

Figure 2 shows how this circuit may be slightly modified to provide a simplercircuit for lamps of smaller wattage. The circuit may be connected directly to ordinary volt domestic lines and the auto-transformer may be eliminated. The condenser used for correcting the power factor may or may not be used. incandescent lamp may be used as a ballast instead of an inductance coil as shown in Figure 1.

What I claim is:

1. Lighting apparatus comprising: two discharge lamps, each having two electrodes of the filamentary type; a ballast impedance; a transformer; and a switch; the ballast impedance, a filament of one lamp, the switch, the transformer primary, and a filament of the other lamp being all connected in series, the transformer secondary being connected to supply both of the other filaments when the switch is closed.

2. Lighting apparatus comprising:. two discharge lamps, each having two electrodes of the filamentary type; a ballast impedance; a transformer; and a switch; the ballast impedance, a filament of one lamp, the switch, the transformer primary, and a filament of the other lamp being all connected in series, the transformer secondary being connected to supply both of the other filaments when the switch is closed;

and a condenser across the primary of the .trans former.

HENRY J.

In this case, an 

